Guys,
I think we are in danger of getting into "simitis" here. It depends on the circumstances.
We have to practice Emergency Evacuation in the sim, and for a realistic scenario sometimes an engine fire warning is included for realism.
If the Engine fire warning is out and the Fire Chief confirms there is no danger - why would you want Evacuate and break a few elderly bones? You always have the option to evacuate some seconds later if it really was required.